Rapid development has been observed in the field of computer peripheral devices. A variety of read/write media and associated read/write unit have been developed, including tapes and tape drives, floppy disks and floppy disk drives, hard disks and hard disk drives, as well as the latest IC cards and IC read/write units. The aim of development of these media is usually to decrease their size and at the same time increase their memory capacity. The latest IC card is desirable because of its light weight, small dimensions and consequent retractability, replaceability, and portability, despite a large memory size nearly equivalent to that of a hard disk.
A problem is that conventional IC drives are adapted to receive only one IC card. To receive two IC cards, a computer or personal computer would normally require two IC read/write units. The most readily envisaged configuration would be to have each IC read/write unit occupy a specific amount of space, in which case the space occupied by two IC read/write units would be twice the space occupied by one IC read/write unit. To reduce the size of the computer or personal computer, it would instead be desirable to provide an IC drive which is adapted to receive more than one IC card.